Objective A 50-100-mg rectal dose of nonsteroidal anti-inflammatory drugs (NSAIDs; diclofenac or indomethacin) has been shown to prevent post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). However, this is higher than the recommended 25-mg dose that is commonly administered to Japanese patients. The objective of this study was to evaluate the safety and efficacy of 25-mg rectal dose of diclofenac in preventing PEP.

Methods Between January 2016 and March 2017, a total of 147 patients underwent ERCP with or without the rectal administration of diclofenac (25 mg) 20 min before the procedure. A retrospective analysis was conducted to evaluate the efficacy and safety of this dose in preventing PEP.

Results Thirteen patients (8.8%) developed PEP: 3 patients (4.1%) in the diclofenac group and 10 (13.7%) in the control group (p=0.0460). After ERCP, there were no cases of gastrointestinal hemorrhage, ulceration, acute renal failure, or death. A multivariate logistic regression analysis revealed that the non-administration of rectal diclofenac was a risk factor for PEP (odds ratio=3.530; 95% confidence interval=1.017-16.35; p=0.0468).

Conclusions A 25-mg rectal dose of diclofenac might prevent PEP.